Genetics:

Historical Perspective

Ancient History

8000-1000 BC

Domestication & selective breeding

Cattle

Horses

Dogs

800 BC

Artificial Pollination

Date palms

Maize

Heredity

What is actually being transmitted, and how

does it happen?

What is the source of the physical substance that

gives rise to offspring?

What is the nature of the generative force that directs

development of that physical substance?

Ancient History

500-400 BC

Hippocrates

On the Seed

Active Humors

Drawn to semen from body

Ancient History

384-322 BC

Aristotle

“Vital Heat” in semen could produce offspring of the

same form

Cooked & shaped menstrual blood

The School of Athens, Raphael

Medieval History

1600s AD

Preformation

Sperm contained complete miniature adults

Homunculus

William Shakespeare

https://www.youtube.com/watch?v=PgSJBAbwv58

Victorian Era

1830

Cell theory – Schleiden & Schwann

All living organisms are composed of basic structural

units called cells

First Wagon Train over Oregon trail, 1830, William Henry Jackson

Victorian Era

1859

On the Origin of Species –

Charles Darwin

Natural Selection

Competition for survival

Organisms w/ traits that are beneficial show increased

chance for survival

If these beneficial traits are heritable, accumulation of these

traits may lead to development of new species over time

Victorian Era

1866

Gregor Mendel

Statistical patterns of inheritance

1869

Friedrich Miescher

Discovered DNA

1879

Walther Flemming

Discovered chromosomes

20th Century

1900

Thomas Morgan

Chromosomal Theory of Inheritance:

Heredity is dependent upon the information contained in

chromosomes, which are contributed by the gametes of

each parent

1920s

Microscopy showed DNA is in chromosomes

20th Century

1941

Beadle & Tatum

One gene, one enzyme hypothesis

1944

Avery, McLeod, and McCarty

DNA is the genetic material – first evidence

1952

Hershey & Chase

DNA is the genetic material – definitive proof

Hershey-Chase Experiment

DNA, not protein, is responsible for

bacteriophage activity in bacterial cells

Phage DNA enters bacterial host cell; protein coat

remains outside

Phage DNA directs reproduction of the virus in

infected bacterial cells

20th Century

1953

Watson & Crick

Double helix structure of DNA

1955

Tjio

Human chromosome number identified: 23 pairs

1966

Nirenberg, Khorana, Ochoa

Identification of the genetic code

20th Century

1970s

Recombinant DNA technology & gene sequencing

techniques developed

1990

Human Genome Project launched

1994

First genetically modified

food approved for sale

20th Century

1995

First complete genome sequenced

Haemophilus influenzae

1996

First mammal cloned – Dolly the sheep

1999

First human chromosome sequenced (#22)

21st Century

2003

Human genome sequence completed

Craig Venter – Celera Genomics

Francis Collins – Nat’l Human Genome Research Institute

3 billion base pairs

~30,000 genes

http://en.wikipedia.org/wiki/File:Craigventer2.jpghttp://en.wikipedia.org/wiki/File:Francis_Collins_official_portrait.jpg

21st Century

Beyond genetics: Genomics

Personalized medicine

Model organisms are used to study genetics